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Change in spark plugs

makomark

makomark

Silver Medal Contributor
"In preparing for all that ann

"In preparing for all that annual maintenance that comes with two engines, I was checking NGK's plug recommendations, for my 454's and see that things have changed. They now recommend the projected nose plug (BPR6FS). Now curious, I checked several other marinized BBC, from the same vintage, and they called for the standard plug (BR6FS). This standard plug is their equivalent of the MR43T.

Anybody know why the change to projected nose?"
 
"No, but if you're having

"No, but if you're having good luck with your present sparkers, why change?

Jeff"
 
"I'm thinking if everythin

"I'm thinking if everything else is constant, no need for change. I know that the chemistry surrounding distilling gasoline has been and probably will continue to change. I did a little searching on the web and can't find any reason not to switch tot he projected nose (better combustion but couldn't find any numbers to substantiate the claims).

The real intriguing part is why only Crusader for the projected nose...???"
 
"it may have something to do w

"it may have something to do with r.f.i..Later model boat have so many electronic pieces on them, they may be trying to clean things up to keep R.F. interference down. Just a thought to get you going. TURBOMAN ROLL TIDE"
 
The old and new reccomended pl

The old and new reccomended plugs are resistor types; they shouldn't make any difference regarding rfi.

thanks for the thought
 
"This spring on eBay I bought

"This spring on eBay I bought a box of 50 NOS MR43T's. Frankly they run so well, I would be hesitant to switch even for the 5 month old plugs in there now. I did have a set of the new NGK's running when I thought I had an ignition problem instead of broken pushrods. Guess I did have an ignition problem after all....it was unable to ignite due to head failure !
"
 
""...set of the [b]new NGK

""...set of the new NGK's running..." which type, Al; the BR's or the BPR's?"
 
"They were the BR ...I am 95%

"They were the BR ...I am 95% sure. Actually goint t the boat today to start a "pre-haul" winterization. Basically Heat up the oils and change it and filters, winterize the A/C and drain the fresh water. Supposed to start getting cold at night around hear so ....AS MUCH AS I HATE TO DO IT....It is tme to come out. I REALLY wanted to go striper fishing but the last several weekends have not cooperated weather wise."
 
FYI. I switched to the project

FYI. I switched to the projected nose NGK plugs due to a recommendation by Mercruiser techs that stated the projected nose plug burns cleaner and is less likely to carbon foul if you run your engines at lower rpm's for extended periods of time to save fuel.
 
"Al - thanks for the answer...

"Al - thanks for the answer.....same situation down here.

Chuck - funny the source for the switch was a Merc tech...I checked NGK's plugs for their BBC, in my year catagories (mid-80s) and they were standard nose plugs. When did you switch and have you noticed any difference?"
 
I switched to projected NGK pl

I switched to projected NGK plugs in September so it's still a little early to draw a conclusion but my problem was excessive carbon build up in the cylinders of my 1200 hr small blocks. My compression ranged from 165 to 178psi. Since then my compression has stabilized around 145-150psi. I suspect that it will drop further as I burn the carbon out. Compression should be around 120-125psi. I've had her up to 4400 rpm on several runs for short periods and she seems to run better with each run. This is why I responded to your post because as we all run our boats slower to save fuel we need to be aware of the potential side effects of carbon build up in these high performance engines. And as a result of diagnosing my carbon problem I changed to projected plugs & high output coils to help minimize the carbon build up. I also make sure I run her up on plane for a short time each time I cruise any distance at low rpm.
 
Chuck:

glad to hear you hav

Chuck:

glad to hear you have some verification of the claims I've read about re the projected nose plug. I think I'll give them a go as there are available for the same $$.

tnx mark
 
"Chuck's doing something r

"Chuck's doing something right with 1200 hours on his SB's. Long nose plugs achieve a more even flame front propagation, more thorough combustion and cleaner exhaust emissions over the life of the engine. I try to add a touch of anti seize compound on the threads when screwing in new plugs, btw."
 
I got over 3000 hrs on the big

I got over 3000 hrs on the big blocks with the MR43T/BR6FS plug. That was before the ethanol started showing up on the marine fuel docks
 
"..." I try to add a touch

"..." I try to add a touch of anti seize compound on the threads when screwing in new plugs..."

NEVER, EVER install plugs in a marine engine without anti-seize! Trust me on this.

Jeff"
 
"I'm one of those guys who

"I'm one of those guys who always seem to learn things the hard way. But I do learn, and I rarely repeat the same mistake.

After blowing up Mr Port, the insurance company insisted that the marina do a compression test on Mr. Starboard. They not only reinstalled the old plugs without never seize on the threads, they over tightened one. Years later, when changing out the plugs, one of them snapped off in the head. Had to pull the perfectly good running motor apart to get the remains out.

I learned a few new words that day!

Jeff"
 
"Jeff, My greatest new word of

"Jeff, My greatest new word of the ENTIRE YEAR was the BFH....That will stand out for the rest of my life.

For those not familiar: A "BFH" is a universal removal tool and can be used in many stages of a re-build. The range in size from 5 to 16 lbs and the 3 foot long handle is available in non corrosive fiberglass or wood."
 
"Not to get off topic, but the

"Not to get off topic, but there is an art to using a BFH. I used to own an automobile garage and when John was over there banging away with a BFH - you didnt worry as he knew the art. But when Hal was over there banging away with a BFH - you went to see what he was breaking and how you could help. There is an art to the BFH.

Started using anti-seize on all spark plugs in customer cars and it took a couple years before most cars stared coming in with easy to remove plugs. The Fastjeff drill is never fun."
 
"Gotta relate a story on BFH.

"Gotta relate a story on BFH. I labeled a drawer of my tool box the "BFH Dept". My Mom spotted that and asked me what it meant!

Never changed the subject so fast in my life. Needless to say, the drawer is no longer labeled.

Jeff"
 
You just need to think if some

You just need to think if something else... like "NFW!" means "Not Financially Workable" when we all know othewise.

Mom - "Big Fat Hammer"

Happy Thanksgiving!
 
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